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ExxonMobil working to bring extraction ideas for oil shale to surface

ExxonMobil has put its Colony Mine testing to good use as it has awaited the opportunity to develop a test oil shale plot on federal land, a company official said.

By treating and using water produced by its operation and using air to cool its power generation and other measures, ExxonMobil is expecting to need one to two barrels of water for each equivalent of a barrel of oil it produces, Tom Yelverton of ExxonMobil said Wednesday during a Grand Junction Area Chamber of Commerce energy briefing.

Different approaches require different amounts of water, but the Rand Corp. said in 2005 that “several” barrels of water were needed to produce the equivalent of a barrel of oil.

ExxonMobil is one of three companies whose applications for leases to test methods of extracting petroleum from oil shale got preliminary approval last month from the U.S. Department of the Interior.

ExxonMobil has begun a process of environmental review that could last a year or more before the federal government issues a lease. At best, commercial production is a decade away and most likely more, Yelverton said.

The research, demonstration and development leases last for 10 years, and Yelverton said he expects ExxonMobil to need all that time and possibly more.

ExxonMobil has been working in the Colony Mine on its trademarked Electrofrac method of heating shale buried some 2,000 feet below the surface to release a form of hydrocarbon called kerogen, which can be refined to produce gasoline and other petroleum products.

The Electrofrac method calls for shale to be heated in place by running an electrical current through a conductive material at the bottom of the Green River formation, which contains the richest deposits of oil shale in the world.

Inside the Colony Mine, ExxonMobil has succeeded in fracturing a 100-foot-long crevice, which it has filled with conductive material, and has been heating the area for a couple months now, Yelverton said.

The process of heating the rock to release kerogen is years long. Once freed from its rock matrix, the kerogen, as well as natural gas, will expand and migrate to wells where it can be recovered to the surface by conventional drilling methods.

ExxonMobil officials will continue working in the Colony test site as the company pursues its lease, but no immediate increase in employment is in the offing, Yelverton said.

ExxonMobil’s interest in shale is unlikely to diminish because of the significant size of the resource, estimated to contain the equivalent of 1 trillion to 2 trillion barrels of oil, Yelverton said.

“It’s just mind-boggling what you’re sitting on here” in western Colorado, Yelverton said.